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    <script>
        var a = 10;
        ++a;//  ++a=11 a=11
        var b = ++a + 2; b = 13
        console.log(b);

        var c = 10;
        c++; //c++=11 c =11
        var d = c++ + 2; //d=13
        console.log(d);



        var e = 10;
        var f = e++ + ++e;//e++ =10 e=11  ++e=12
        console.log(f);//f=10+12=22 
    </script>
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